I am trying to execute a command using Vi or ex to edit a file by deleting the first five lines, replace x with y, remove extra spaces at the end of each line but retain the carraige returns, and remove the last eight lines of the file, then rename the file into a shell script and run the new script from the current script.
This will be something that is scheduled in cron. I have been looking for a simple way to do it using the command line or a Vim script or something.
Any ideas? The format of the input file does not change, just the amount of lines, so I can't specify the line numbers for the last eight lines.
You actually have about half a dozen questions here. Here's an answer for the first five which are probably the ones you'll have the most difficulty solving:
sed -e ':label' -n -e '1d' -e 's/x/y/g' -e 's/[ \t]*$//g' -e '1,9!{P;N;D};N;b label' file.txt > script.sh
Vi is an interactive editor. You probably don't want to use it for something that'll be run by cron. Also, I agree with the comments saying this is probably a bad idea. Be that as it may:
printf 'one\ntwo\nthree\nfour\nfive\necho x \n1\n2\n3\n4\n5\n6\n7\n8\n' \
| sed '1,5d;s/ *$//;s/x/y/' \
| tail -r | sed 1,8d | tail -r \
| sh
Our first sed script does most of the work. We reverse the lines with tail -r, then delete the first 8 lines, then reverse again. That trims off the last 8 lines.
Note that on Linux systems (or any with GNU coreutils), you may also have a tac command which reverse lines, but tail -r is more portable.
Also, the final | sh simply runs the output. If you REALLY want to save this as a script, you can do that by redirecting the output to a file ... but I'll leave at least that to your imagination. Can't do all your scripting for you, can we?! :-)
To edit a file by a script, you could use ed (even if it hard to learn or remember).
You could also use some scripting language (Python, Perl, AWK, Ruby) to achieve your goal.
Related
I'm trying to use the sed command in terminal to replace a specific line in all my text files with a certain extension by a specific string:
sed -i.bak '35s/^.*$/5\) 1\-4/' fitting_file*.feedme
So I am trying to replace line 35 in each of these files with the string "5) 1-4". When I run an ls fitting_file*.feedme | wc -l command in this directory, I get 221 files. However, when I run the above sed command, it only edits the FIRST file in the order of ls fitting_file*.feedme. I know this because grep '5) 1-4' fitting_file*.feedme continually only returns the first file on the list after I run the replacement command. I also tried replacing fitting_file*.feedme with a space-separated list of a couple of these files in my sed command as a test, but it still only operated on the one I chose to list first. Why is this happening?
sed operates on a single stream. It essentially concats all the files together and treats that as a single stream. So it replaces the 35th line of the big concatenated stream.
To see this, make a 20 line file called A and a 20 line file called B. Apply your sed command as
sed -i.bak '35s/^.*$/5\) 1\-4/' A B
and you will see the 15th line of B replaced.
I think this should answer your direct question. As far how to get done what you like, I assume you've already figured out that wrapping your sed command in a for is one way to do it. :)
Try
Create a file containing your sed instruction like this
#!/bin/bash
sed -i.bak '35s/^.*$/5\) 1\-4/' $1
exit 0
and call it prog.sh. Next make it executable :
chmod u+x prog.sh
now you can solve your problem using
find . -name fitting_file\*.feedme -exec ./prog.sh {} \;
You could do all this on one line but frankly the number of escapes required is a bit much. Good luck.
To do what you're trying to do without using a shell loop is:
awk -i inplace -v inplace::suffix=.bak 'FNR==35{$0="5) 1-4"}1' fitting_file*.feedme
Note that unlike sed which can just count lines across all input files, awk has NR to track the number of records (lines by default) across all files and FNR for the same but just within the current file.
The above uses GNU awk for inplace editing just like GNU sed has -i for that. The default awk on MacOS is BSD awk, not GNU awk, but you should install GNU awk as it doesn't have all the bugs/quirks that BSD awk does and it has a ton of extremely useful extensions.
If you just want to use MacOS's awk then it'd be something like:
find . -name 'fitting_file*.feedme' -exec sh -c "\
awk 'FNR==35{\$0=\"5) 1-4\"}1' \"\$1\" > \"\$1.bak\" &&
mv -- \"\$1.bak\" \"\$1\"
" sh {} \;
which is obviously getting kinda complicated - I'd probably put the awk+mv script in a file to execute from sh -c or just resort to a shell loop myself if faced with that alternative (or a similar quoting nightmare with xargs)!
i want to execute a command as follows on my bash terminal:
sed -i '6i `sed '1!d' input.in`' out
with which i can insert at line 6 of file out (with replacing -i option) the result of the sed '%1!d' input.in command. I haven't found anything useful, and have tried both `com`, $(com) and com | sed -i '6i ' out, where com stands for sed '%1!d' input.in. I don't have any problem changing the syntax of the whole command but i want it to be written in one line on terminal use sed.
Thanks for listening,
awaiting your answer.
For EdMorton:
Example Input:
input.in:
into a lake.
out:
Mary was runing around a pond and fell
into a lake.
Mary fell into a what?
Desired Output:
Mary was runing around a pond and fell
into a lake.
Mary fell into a what?
into a lake.
Try using r on standard input instead of i.
sed '%1!d' input.in |
sed -i '6r /dev/stdin' out
If your platform doesn't support /dev/stdin or /dev/fd/0, see if your sed supports - to mean standard input ... or, in the worst case, resort to a temporary file.
As commenters have already pointed out, %1!d does not appear to be a valid command in most sed dialects, but that is basically unimportant here. (If you mean to print just the first line, maybe you mean sed '1!d', although sed 'p;q' does that more efficiently.)
sed is for simple substitutions on individual lines, that is all. For anything else you should be using awk.
Given this modified input file
$ cat input.in
a Windows folder C:\Windows\Temp
Here is what the sed solution you posted in your comments does:
$ sed '1!d' input.in > temp.of.in && sed "6i `cat temp.of.in`" out
Mary was runing around a pond and fell
into a lake.
Mary fell into a what?
a Windows folder C:WindowsTemp
and here is what an awk solution does more efficiently and accurately and without a temp file:
$ awk 'NR==1{x=$0;nextfile} FNR==6{print x} 1' input.in out
Mary was runing around a pond and fell
into a lake.
Mary fell into a what?
a Windows folder C:\Windows\Temp
Notice the awk solution preserved the path-separator backslashes while the sed one stripped them. Also note that you should really add && rm temp.of.in to the end of your sed command line to clean up the temp file and you should be using $(..) to execute your command, not obsolete backticks.
The awk solution uses GNU awk for ;nextfile, with other awks you'd replace that with }NR==FNR{next or similar but since you are using GNU sed I assume you have GNU awk too.
Note that if you DID have a burning desire to use sed and accept it won't exactly reproduce the input, there are simpler, more efficient ways to do what your current script does, e.g.:
sed "6i $(head -1 input.in)" out
or even your original idea, just rewritten to remove the obsolete backticks and negative logic of 1!d:
sed "6i $(sed -n '1p' input.in)" out
But seriously - just use awk. For anything other than simple substitutions on individual lines it's much more robust, efficient, clear, portable, extensible, etc. etc. than sed.
EDIT To address the questions in your comments:
Can you explain the arguments on awk.
There are no arguments, just a script that says: If this is the first line read from the first file save it in variable x then move on to the next file. If this is line 6 of the 2nd file print the contents of variable x. For every line of the 2nd file, print it (the 1 is idiomatic but a bit tricky at first glance - it's a true condition so it invokes the default action of printing the current input, equivalent to just writing {print}.
how can i replace the out file with the output (without using '>') as the option -i does on sed and avoid printing it to stdout? Just like GNU sed has -i, GNU awk has -i inplace. Be careful though because, just like with sed, it applies to every input file so if you don't print the contents of the first file then when the script is done the first file will be empty. There's various was to deal with that, including simply printing the lines from file 1 or turning inplace editing on/off in BEGINFILE/ENDFILE blocks, see https://www.gnu.org/software/gawk/manual/gawk.html#Extension-Sample-Inplace, but IMHO awk 'script' file1 file2 > temp && mv temp file2 is the simplest and clearest as well as being portable to all awks/seds/whatever.
Also if there is a multiline solution like "take lines 1 to 4" from "input.in" and drop them on line 6 of "out"? No problem:
.
awk '
NR==FNR { if (NR<=4) x=x $0 ORS; else nextfile }
FNR==6 { printf "%s", x }
{ print }
' input.in out
I changed the 1 from the previous script to { print } for clarity.
I am quite new to shell scripting.
I am scraping a website and the scraped text contains a lot of repetitions. Usually they are the menus on a forum, for example. Mostly, I do this in Python, but I thought that sed command will save me reading and printing the input, loops etc. I want to delete thousands of repeated lines from the same single file. I do not want to copy it to another file, because I will end up with 100 new files. The following is a shadow script which I run from the bash shell.
#!/bin/sed -f
sed -i '/^how$/d' input_file.txt
sed -i '/^is test$/d' input_file.txt
sed -i '/^repeated text/d' input_file.txt
This is the content of the input file:
how to do this task
why it is not working
this is test
Stackoverflow is a very helpful community of programmers
that is test
this is text
repeated text is common
this is repeated text of the above line
Then I run in the shell the following command:
sed -f scriptFile input_file.txt
I get the following error
sed: scriptFile line 2: untermindated `s' command
How can I correct the script, and what is the correct syntax of the command I should use to get it work?
Any help is highly appreciated.
assuming you know what your script is doing, it's very easy to put them into a script. in your case, the script should be:
/^how$/d
/^is test$/d
/^repeated text/d
that's good enough.
to make the script alone to be executable is easy too:
#!/usr/bin/env sed -f
/^how$/d
/^is test$/d
/^repeated text/d
then
chmod +x your_sed_script
./your_sed_script <old >new
here is a very good and compact tutorial. you can learn a lot from it.
following is an example from the site, just in case the link is dead:
If you have a large number of sed commands, you can put them into a file and use
sed -f sedscript <old >new
where sedscript could look like this:
# sed comment - This script changes lower case vowels to upper case
s/a/A/g
s/e/E/g
s/i/I/g
s/o/O/g
s/u/U/g
Wouldn't it be easier to do it with egrep followed by a mv, for example
egrep -v 'pattern1|pattern2|pattern3|...' <input_file.txt >tmpfile.txt
mv tmpfile.txt input_file.txt
Each pattern would describe the lines being deleted, much like in sed. You would not end up with additional files, because the mv removes them.
If you have so many pattern, that you don't want to specify them directly on the command line, you can store them in a file use the -f option of egrep.
I want to edit a file from the command line, because opening it in vim or other editors takes forever (a large file). I want to add a string ('chr') to the beginning of every line that is not commented out with a #. The command I am using is this:
cat '/home/me/37.vcf' | sed s/^/chr/>'sp.vcf'
But it adds a chr to the beginning of EVERY line and a > to the END of every line. I don't want either of those things to occur.
Can anyone offer any suggestions to improve my results?
To apply the substitution to only the lines that don't start with a #:
sed '/^[^#]/s/^/chr/' file > output
Note: the command cat is for concatenating files, it is useless here.
You can syntax error in your sed command. Use this syntactically correct sed command:
sed -E 's/^([^#]|$)/chr/' /home/me/37.vcf > sp.vcf
OR on Linux:
sed -r 's/^([^#]|$)/chr/' /home/me/37.vcf > sp.vcf
This might work for you (GNU sed):
sed '/^\s*#/!s/^/chr/' file > new_file
I have a huge SQL file that gets executed on the server. The dump is from my machine and in it there are a few settings relating to my machine. So basically, I want every occurance of "c://temp" to be replace by "//home//some//blah"
How can this be done from the command line?
sed is a good choice for large files.
sed -i.bak -e 's%C://temp%//home//some//blah%' large_file.sql
It is a good choice because doesn't read the whole file at once to change it. Quoting the manual:
A stream editor is used to perform
basic text transformations on an input
stream (a file or input from a
pipeline). While in some ways similar
to an editor which permits scripted
edits (such as ed), sed works by
making only one pass over the
input(s), and is consequently more
efficient. But it is sed's ability to
filter text in a pipeline which
particularly distinguishes it from
other types of editors.
The relevant manual section is here. A small explanation follows
-i.bak enables in place editing leaving a backup copy with .bak extension
s%foo%bar% uses s, the substitution command, which
substitutes matches of first string
in between the % sign, 'foo', for the second
string, 'bar'. It's usually written as s//
but because your strings have plenty
of slashes, it's more convenient to
change them for something else so you
avoid having to escape them.
Example
vinko#mithril:~$ sed -i.bak -e 's%C://temp%//home//some//blah%' a.txt
vinko#mithril:~$ more a.txt
//home//some//blah
D://temp
//home//some//blah
D://temp
vinko#mithril:~$ more a.txt.bak
C://temp
D://temp
C://temp
D://temp
Just for completeness. In place replacement using perl.
perl -i -p -e 's{c://temp}{//home//some//blah}g' mysql.dmp
No backslash escapes required either. ;)
Try sed? Something like:
sed 's/c:\/\/temp/\/\/home\/\/some\/\/blah/' mydump.sql > fixeddump.sql
Escaping all those slashes makes this look horrible though, here's a simpler example which changes foo to bar.
sed 's/foo/bar/' mydump.sql > fixeddump.sql
As others have noted, you can choose your own delimiter, which would prevent the leaning toothpick syndrome in this case:
sed 's|c://temp\\|home//some//blah|' mydump.sql > fixeddump.sql
The clever thing about sed is that it operating on a stream rather than a file all at once, so you can process huge files using only a modest amount of memory.
There's also a non-standard UNIX utility, rpl, which does the exact same thing that the sed examples do; however, I'm not sure whether rpl operates streamwise, so sed may be the better option here.
The sed command can do that.
Rather than escaping the slashes, you can choose a different delimiter (_ in this case):
sed -e 's_c://temp/_/home//some//blah/_' file1.txt > file2.txt
perl -pi -e 's#c://temp#//home//some//blah#g' yourfilename
The -p will treat this script as a loop, it will read the specified file line by line running the regex search and replace.
-i This flag should be used in conjunction with the -p flag. This commands Perl to edit the file in place.
-e Just means execute this perl code.
Good luck
gawk
awk '{gsub("c://temp","//home//some//blah")}1' file